Multiple filament rectifier



Aug. 2, 1932. c, HORN 1,869,560

MULTIPLE FILAMENT RECTIFIER Filed Jan. 25, 1928 INVENTOR CZfI/Ff/VCf A? HU/F/V ATTORNEY Patented Aug. 2, 1932 UNITED STATES PATENT OFFICE CLARENCE A. HORN,

OF RAHWAY, NEW JERSEY, ASSIGNOR TO ARCT'U'RUS RADIO TUBE MULTIPLE FILAMENT RECTIFIER Application filed January 25, 1928. Serial No. 249,256.

This invention relates to vacuum tubes adapted to be used to rectify alternating current and particularly that type of tube which is adapted to rectify both sides of the alternating current wave.

One of the objects of the invention is to provide a rectifier tube of the heater type which will operate at a relatively low voltage so that the same may be used in standard rectifying devices such as B battery eliminators.

Another object of the invention is to provide a rectifying tube which will operate at low voltages and which is adapted to use a carbon filament in order to heat the cathode.

Another object of the invention is to provide a rectifying tube in which a pair of filaments are used connected in parallel.

Other objects of the invention and objects relating to economies of manufacture and design will be evident as the description of the invention proceeds.

One embodiment illustrated in the accompanying drawing, which Fig. 1 is an elevation of a rectifying tube embodyin of the invention has been in the invention, certain portions being bro en away for clearness;

Fig. 2 is a horizontal sectional view of the elements of the tube taken substantially on the line 22 of Fig. 1; and

Fig. 3 is a side view of the elements of the tube.

The tube comprises the usual envelope 1O sealed in a base 11 which is adapted to carry the terminals for connection in the circuit. A stem 12 is provided to support the elements of the tube through a plurality of conductors which are sealed therein. Two of these conductors 13 and 14 extend upwardly a short distance and then are bent rearwardly and upwardly again forming supports 15 and 16 respectively for the tubular plates 17 and 18 which are mounted spaced apart in the upper end of the tube. The plates 17 and 18 are preferably cylindrical and formed each of a single flat strip of metal bent in the form of a cylinder and having extended ends whlch form flanges 19 and 20 which may be provided at their ends with cylindrical grooves to form sockets to receive the supports 15 and 16. The plates 17 and 18 are substantially centrally disposed in the tube directly over the stem, as clearly indicated in Fig. 3.

Inside of the plates 17 and 18 are cathodes 21 and 22. These cathodes are preferably cylindrical and are somewhat longer than the plates 17 and 18 so that they extend out of the top and bottom thereof. The cathodes are covered with the usual electronemitting oxides as is well known in the art. The lower ends of the cathodes 21 and 22 are supported by a single support 23, which is sealed in the center of the press 12, by means of two strips 24 and 25 which surround the lower ends of the cathodes and are welded thereto and are in turn welded to the support 23. The support 23 is bent outwardly immediately above the point of connection of the strips 24 and 25 and a vertical support- 26 is welded to the end thereof. The support 26 extends upwardly above the tops of the cathodes and may be provided with a glass bead 27 into which angular wires 28 and 29 may be sealed for the purpose of supporting the uprights 15 and 16 to which they may be welded. The upper ends of the cathodes 21 and 22 are surrounded by strips 30 and 31 respectively which may extend rearwardly and inwardly and be welded to the upper end of the support 26, as indicated in Fig. 2. In order to make this connection for the support of the upper end of the cathodes more rigid a cross piece 32 may be welded across the two strips 30 and 31 at a point adjacent the cathode, thus forming a rigid triangular support for the upper ends of the cathodes.

Filaments 33 and 34 are mounted within the cathodes 21 and 22 respectively and are substantially concentric therewith and these filaments may be supported at their lower ends by support conductors 35 and 36 which are sealed in the press 12, as shown in Fig. 1.

The conductors 35and 36 may be bent -inwardly at their lower ends in order to space them from the conductors for the plates. The upper ends of the filaments 33 and 34 may be supported by springs 37 and 38 which may be welded to the upper end of the support 26 and to the upper ends of the filaments and are adapted to maintain the filaments slightly under tension to compensate for variations in length due to temperature chan es and to prevent the filament from touchmg the sides of the cathodes.

The springs 37 and 38 form electrical connections from the upper ends of the filaments 33 and 34 to the support 26 which is connected through the support 23 to one of the filament terminals 39 of the tube by means of a wire 40. The lower ends of the filaments 33 and 34 are connected by means of the conductors 35 and 36 through the stem 12 to the other filament terminal 41 by means of the wires 42 and 43 respectively which are both brought down to the terminal 41.

From this construction it will be evident that the two filaments 33 and 34 are connected in parallel. It will also be noted that both the upper and lower ends of the cathodes are connected to the supports 23 and 26 by means of the strips 30 and 31 and 24 and 25 so that the terminal 39 forms the connection to the cathodes of the tube.

The two plates 17 and 18 are connected to the terminals 44 and 45 respectively by means of wires 46 and 47 which are attached to the conductors 13 and 14 in the stem 12. The usual glass tubes 48 may be provided surrounding any of the wires 40, 42, 43, 46 or 47 as desired, in order to maintain these wires insulated from each other within the base of the tube.

The tube may be connected up in any conventional way, as indicated in Fig. 1, where in an alternating current transformer 49 has its primary 50 connected to a source of alternating current, not shown, and its secondary 51 divided into two parts 52 and 53, the latter constituting the source for the filament current and the former constituting the source for the current to be rectified. The two ends of the secondary 53 are therefore connected to the terminals 39 and 41 by the leads 54 and 55 respectively and the ends of the secondary 52 are connected by the leads 56 and 57 to the terminals 44 and 45 respectively constituting the connections to the plates 17 and 18. The desired load 58 may be connected between substantially the mid point of the secondary 52 and the cathode terminal 39 of the tube, the filter 59 be ing also connected in series if desired.

- From the above description it is evident that I have provided a rectifying tube in which the filaments operate in parallel so that sufficient heat may be generated in the cathodes to produce rectification with the use of low voltages. The tube as described is adapted to rectify a current of approximately two amperes at a filament voltage of approximately five and one-quarter volts and when this tube is under load and the cathodes emitting electrons, the same are not raised to such a temperature as will render them brightly incandescent, with the result that the life of the tube is exceptionally lon l ith the filaments operated in parallel, if one should burn out the other may still continue to function, with the result that the tube will rectify one-half of the alternating current wave. This is a marked advantage over full'wave rectifying tubes having filaments in series and which, if the filament breaks at any point the whole tube is put completely out of service.

While I have shown and described one embodiment of the invention, I do not desire to limit myself to that specific embodiment, except as defined in the appended claims, as it is evident that many changes may be made in the construction without departing from the spirit of the invention.

What I claim is:

1. A rectifying tube comprising a pair of tubular anodes, a tubular cathode within each anode, a heater within each cathode, a support spaced from said anodes, a connection from one end of each cathode to said support to maintain said ends in position with respect to said anodes and to electrically connect said ends to each other and to said support, a pair of springs attached at one end to said support and having their other ends attached one to each heater, said springs being flexed out of their normal position whereby said heaters are maintained .taut and in position with respect to said cathodes, said springs formingv an electrical connection between said heaters and said support.

2. A rectifier tube comprising a plurality of associated anodes and cathodes, a metallic support spaced therefrom, means connecting the upper ends of said cathodes to said support, means connecting the lower ends of said cathodes to said support,'a heater adjacent each cathode and means connecting one end of each heater to said support. 7

3. A rectifying tube comprising a plurality of plates, a separate connection for each of said plates, a cathode for each of said plates,

a heater for each of said cathodes, a support,-

' 4. A rectifying tube comprising a pair of hollow plates, a hollow cathode within each plate, a heater within each cathode, a conductive support spaced from said plates, a conductive connection from one end of each cathode to said support to maintain said ends in position with respect to said plates and to electrically .connect said ends to each other and to said su port, and conductive means attached to sai support supporting the said heaters in substantially taut condition and forming an electrical connection between said heaters and said support.

In testimony whereof, I afiix my signature.

CLARENCE A. HORN. 

